Oceanic Spawning Migration of the European Eel ( Anguilla anguilla )

Abstract

European eels (Anguilla anguilla) undertake a approximately 5000-kilometer (km) spawning migration from Europe to the Sargasso Sea. The larvae are transported back to European waters by the Gulf Stream and North Atlantic Drift. However, details of the spawning migration remain unknown because tracking eels in the Atlantic Ocean has, so far, eluded study. Recent advances in satellite tracking enable investigation of migratory behavior of large ocean-dwelling animals. However, sizes of available tags have precluded tracking smaller animals like European eels. Here, we present information about the swimming direction, depth, and migratory behavior of European eels during spawning migration, based on a miniaturized pop-up satellite archival transmitter. Although the tagging experiment fell short of revealing the full migration to the Sargasso Sea, the data covered the first 1300 km and provided unique insights.

Changes in European eel ovary development and body and ovary chemistry during stimulated maturation under controlled conditions: preliminary data

“…However, van Ginneken et al (2005b) and Palstra and van den Thillart (2010) estimated that about 20 % of the energy consumed for swimming is produced from proteins. Considering the fact that eel are known to be much more effective swimmers than thought before (van Ginneken et al 2005b;Palstra and van den Thillart 2010;Clevestam et al 2011), and they save considerable amounts of energy when swimming to the spawning ground and that they swim (at least initially) at water temperatures considerably lower than those at which metabolic studies have been conducted (Aarestrup et al 2009), it may be accepted that energy saving for swimming can be even more effective than originally assumed. It is all the more so that, as these studies have shown, eel usually make use of sea currents rather than swimming upstream.…”

Predator transitory spillover induces trophic cascades in ecological sinks

“…In particular, cross-habitat fluxes of organisms (mediated by passive transport or active migration) occur between natural habitats and across natural/anthropogenic systems, at various geographical scales (5)(6)(7)(8)(9). In heterogeneous landscapes, a particular case of cross-habitat fluxes is represented by source-sink dynamics in which a population from a productive source habitat maintains by migration populations in sink habitats where local reproduction is insufficient to compensate for mortality (10,11).…”

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“…Hence, this technology provides information on the fish position at pop-up time, and stored light, temperature and depth data can be used to calculate fish movements between tagging and the pop-up location (see below). PSATs are relatively large and have to be attached externally, which limits size and species of fish that can be tagged, although some PSATs are now small enough to be used on European silver eel (Anguilla anguilla) (Aarestrup et al, 2009) and adult Atlantic salmon (Chittenden et al, 2013b). The advantage with these tags is that they do not need to be recovered to retrieve data, data is also retrieved from fish that dies (which is often as important as getting data from only those surviving), and an accurate pop-up location is achieved.…”